1. introduce implementations of HTTPTransport and HTTPClient
that apply an error wrapping policy using the constructor
for a generic top-level error wrapper
2. make sure we use the implementations in point 1 when we
are constructing HTTPTransport and HTTPClient
3. make sure we apply error wrapping using the constructor for
a generic top-level error wrapper when reading bodies
4. acknowledge that error wrapping would be broken if we do
not return the same classification _and_ operation when we wrap
an already wrapped error, so fix the to code to do that
5. acknowledge that the classifiers already deal with preserving
the error string and explain why this is a quirk and why we
cannot remove it right now and what needs to happen to safely
remove this quirk from the codebase
Closes https://github.com/ooni/probe/issues/1860
This change should simplify the pipeline's job.
Reference issue: https://github.com/ooni/probe/issues/1817.
I previously dismissed this possibility, but now it seems clear it
is simpler to have a very tabular data format internally and to
convert such a format to OONI's data format when serializing.
The OONI data format is what the pipeline expects, but processing
is easier with a more linear/tabular format.
This is the most immediate fix to the issue described by
https://github.com/ooni/probe/issues/1792.
So, the logic was actually miss the increment, which
would have been noticed with proper unit testing.
Anyway, I am not sure why the loop ensues in the first
time. By looking at the headers, it seems we're passing
the headers correctly.
So, even though this fix interrupts the loop, it still
remains the question of whether the loop is legit or
whether we're missing extra logic to properly redirect.
This commit introduce a measurement library that consists of
refactored code from earlier websteps experiments.
I am not going to add tests for the time being, because this library
is still a bit in flux, as we finalize websteps.
I will soon though commit documentation explaining in detail how
to use it, which currrently is at https://github.com/ooni/probe-cli/pull/506
and adds a new directory to internal/tutorial.
The core idea of this measurement library is to allow two
measurement modes:
1. tracing, which is what we're currently doing now, and the
tutorial shows how we can rewrite the measurement part of web
connectivity with measurex using less code. Under a tracing
approach, we construct a normal http.Client that however has
tracing configured, we gather events for resolve, connect, TLS
handshake, QUIC handshake, HTTP round trip, etc. and then we
try to make sense of what happened from the events stream;
2. step-by-step, which is what websteps does, and basically
means that after each operation you immediately write into
a Measurement structure its results and immediately draw the
conclusions on what seems odd (which later may become an
anomaly if we see what the test helper measured).
This library is also such that it produces a data format
compatible with the current OONI spec.
This work is part of https://github.com/ooni/probe/issues/1733.
